Weft thread supply system for looms for weaving



May 5, 1964 H. R. LEYSINGER 3,131,729

WEFT THREAD SUPPLY SYSTEM FOR LOOMS FUR WEAVING Filed Dec. 5, 1960 5 Sheets-Sheet 1 y 1964 H. R. LEYSINGER 3,131,729

WEFT THREAD SUPPLY SYSTEM FOR LOOMS FOR WEAVING Filed Dec. 5, 1960 5 Sheets-Sheet 2 J 3 I 'e\ \a 15 /M\ May 5, 1964 H. R.'LEYSINGER 3,131,729

WEFT THREAD SUPPLY SYSTEM FOR LOOMS FOR WEAVING Filed Dec. 5, 1960 5 Sheets-Sheet s 43 H 6. wm mm 2 v T May 5, 1964 H. R. LEYSINGER 3,131,729

WEFT THREAD SUPPLY SYSTEM FOR LOOMS FOR WEAVING Filed Dec. 5, 1960 5 Sheets-Sheet 4 0 00 /0 0 0 0 0 0 0 000000 B I w n 0 0 0 0 0 0 fl.

May,5, 1964 H. R. LEYSINGER 3,131,729

WEFT THREAD SUPPLY SYSTEM FOR LOOMS FOR WEAVING Filed Dec. 5, 1960 3,131,729 WEFT THREAD SUPPLY SYSTEM FOR LOOMS FOR WEAVING Hans Rudolf Leysinger, Winterthur, Switzerland, assignor 'to Sulzer Freres, S.A., Winterthur, Switzerland, a corporation of Switzerland Filed Dec. 5, 1960, Ser. No. 73,910

Claims priority, application Switzerland Dec. 4, 1959 3 Claims. (Cl. 139-122) The present invention relates to a weft thread supply system for a loom for weaving of the gripper shuttle type wherein the weft thread is pulled from a storage spool located outside of the shed.

In conventional weaving machines of this type the weft threads travel from the storage spools located outside of the shed and through control devices, such as thread brakes and thread tensioners, to devices for presenting the weft threads to the shuttles. When a shuttle is picked into the shed the weft thread which has been stationary as long as the shuttle did not move is accelerated to the velocity at which the shuttle travels through the shed and is simultaneously pulled from a storage spool. The aforedescribed conventional arrangement has several disadvantages which will be discussed as the description of the invention pro ceeds and which are avoided by the system according to the invention.

The invention provides a weft thread accumulator which substantially continuously receives weft thread from a conventional storage spool and pays out the weft thread according to the operation of the loom. The weft thread accumulating device according to the invention includes rotating winding means for winding weft thread thereonto to form a single layer which moves substantially continuously in the direction of the rotation axis of the winding operation. Whenever a shuttle to which a weft thread is connected is picked into the shed the weft thread is unwound from the aforesaid layer and guided to move in the direction of the rotation axis of the winding means. With the accumulating device according to the invention the thread is substantially continuously pulled from the storage spool at a velocity which is smaller than the peak velocity of the thread during insertion in the shed. The velocity at which the thread is pulled from the storage spool corresponds to the average velocity at which the weft thread is used up by the shuttles. Due to the continuous unwinding of the storage spool and the slow velocity of the thread, thread breakages are avoided. Continuous unwinding at reduced speed from the storage spool is particularly desirable in view of the unavoidable changes of the unwinding resistance which is caused by the changing diameter of the storage spool and position of the thread thereon.

It is true that in the new system the weft thread is intermittently pulled from the accumulating device instead of from the storage spool. However, the single layer of weft thread onthe accumulating device has always the same diameter whereas the diameter of the storage spool changes. Also the resistance to unwinding of the thread from the accumulating device and the tension of thread pulled from the accumulating device are constant in contradistinction to the unwinding resistance and tension of the thread pulled from the storage spool which are changing.

With the system according to the invention the balloon formed by the thread which is unwound from the accumulating device can be maintained due to the continuous rotation of the accumulating device so that the balloon does not collapse between two shuttle picks as is the case with he balloon formed by the threads unwinding from the Storage spools of conventional looms, and twisting and i 'nation of loops are avoided. Twists and loops which quently occur between two picks in the threads pulled United States Patent The elements 30, 34, 38 and 20 3,131,729 Patented May 5, 1964 from the storage spools of conventional looms are straightened out by the shuttles after they are picked into the shed whereby the thread tension, particularly of heavy yarns, is increased and the speed of the shuttles is reduced unless the thread breaks, as it happens once in a while. In conventional looms the twists are not always straightened out and move into the shed which is also not desired.

If the accumulating device is separately driven, the balloon formed by the unwinding thread can be maintained also when the loom stands still so that, when the machine is restarted, thread can be pulled from the balloon and easily accelerated, and twists and loops are avoided.

With the system according to the invention the balloon formed by the thread which is unwound from the storage spool is relatively small due to the smaller rotational speed of the storage spool. The speed of rotation of the balloon formed by the thread unwinding from the accumulating device is also smaller than that of the balloon formed by the thread unwinding from the storage spool of a conventional loom, because the accumulating device is positively rotated and the thread is unwound from the accumulating device in a direction which is opposite to that of the rotation of the device. The system according to the invention is particularly useful when weaving relatively heavy yarns, such as wool, whose balloon is rather heavy. Since the centrifugal force acting on the balloon of the thread unwinding from the accumulating device is relatively small due to the relatively small rotational speed of the balloon, the shuttle moving through the shed is relatively little retarded.

The novel features which are considered characteristic of the invention are set forth with particularity in the appended claims. The invention itself, however, and additional objects and advantages thereof will best be understood from the following description of embodiments thereof when read in connection with the accompanying drawing, wherein: v

FIG. 1 is a longitudinal section of a swiftlike device 'forming a thread accumulator which is part of a weft FIG. 1.

FIG. 3 is across section of the device shown in FIG. 1,

the section being made along line III-III ofFIG. 1.

FIG. 4 is a simplified longitudinal section of a modified device according to the invention.

FIGS. 5 and 6 are diagrams illustrating the operation of the devices shown in FIGS. 1 to 4. I FIG. 7 is a longitudinal section of a modification of a swiftlike device forming the thread accumulator of a weft thread supply system according to the invention.

Referring more particularly to FIG.Ll of the drawing, numeral 5 designates a shaft which is fixed to a part of the frame of a loom for weaving of the gripper shuttle type, not shown, and having astoragespool for a weft thread which spool is placed outside of the shed. Bearing bushings 30 and 34 are supported on theshaft S'by means of rollers 31 and 32. The bushing 34 supports a sleeve 38 which, together with the bushing.30, supports an element 6 forming the star of a swiftlike device. The sleeve 38 has an annularoutside shoulder and the element 6has an annular inside shoulder between which shoulders a coil spring 20, which is coaxial of the shaft 5, ispIaced. rotate together with the element 6, the. latter being axially movable on the sleeve 38. The spring 20 tends to move the element 6 together with the bushing 30 to the left until a conical end surface 21 of the element 6 which end surface is coaxial of the shaft abuts against a corresponding conical surface 28 of a member 9 which is fixed to the shaft 5 and which forms the worm wheel of a worm gear whose purpose will be described later. An axial bearing 33, arranged between the bushing 34 and an annular member 35 which is fast on the stationary shaft 5, and a collar on the bushing 34 prevent axial displacement to the right of the bushing 34 and of the sleeve 38 under the influence of the spring 20.

One end of the element 6 is provided with an annular protuberance 49 which supports, for example, four rollers 2 individually provided with worm wheels which engage the worm 9. An annular protuberance 50 at the opposite end of the element 6 rotatably supports an equal number of rollers 3. The rollers 2 and 3 are arranged in pairs, each pair being placed in a radial plane including the longitudinal axis of the shaft 5. An endless belt 1 extends around each pair of rollers 2, 3, the belt being made of a material having a rough surface, for example leather, rubber, or a synthetic material.

The element 6 is provided with a pulley 7 driven by a belt 8 which is preferably driven by a separate electric motor or by the drive of the weaving machine through an infinitely variable transmission. Upon rotation of the element 6 around the shaft 5 the belts 1 move in the directions of the arrows 4, i.e. the outer runs of the belts move from left to right, as seen in FIG. 1. A weft thread 23 pulled from a weft thread storage spool, not shown, runs through a thread brake 13 and a guide eye 12 tangentially on the swift and is wound thereonto for producing a single layer 22 comprising, for example, between 40 and 50 windings. The thread 23 unwinding from the swift forms a balloon 41 which rotates around the axis of the shaft 5, the thread 23 subsequently passing through an eye 43 mounted in a shield 42. After passage through the eye 43 the weft thread travels through a thread tensioner, and therefrom to a device for presenting the weft thread to a shuttle. These elements do not form part of the present invention and are not illustrated. A disc 44 is mounted to the right end of the shaft 5 and has a rim which is bent over the rollers 3 for preventing entanglement of the thread 23 with the swift mechanism, should the balloon 41 collapse.

Levers 15 are pivoted by pins 16 to the annular protuberance 50 at the right side of element 6 to swing in radial planes including the longitudinal axis of the shaft 5. Each lever 15 has an arm portion which is substantially parallel to the shaft 5 and has a U-shaped cross sectional configuration and forms a channel 45 for receiving the outer run of a belt 1. The lateral portions of the aforedescribed arm portion are provided with guide surfaces 46 which are so placed that undesired surplus windings of the layer 22 of weft thread 23 wound on the swift run onto the guide surfaces. Each lever 15 is provided with a nose 17 extending into a cavity 37 of the sleeve 38.

The device illustrated in FIGS. 1 to 3 operates as follows:

The rotational speed of the swift is so adjusted that the amount of weft thread 23 running onto the swift per time unit corresponds to the amount of weft thread unwound from the swift and passing through the eye 43 so that the axial extension of the thread layer 22 remains constant. The levers 15 are pressed outward by centrifugal force against the outer runs of the belts 1. If, for any reason, less thread is pulled through the eye 43 from the swift than is supplied through the eye 12 to the swift, the axial extension of the layer 22 of thread windings in FIG. 1 increases towards the right and surplus windings are pushed onto the guide surfaces 46 of the levers 15, whereby the levers are rocked in counterclockwise direction. This causes movement of the element 6 together with the pin 16 to the left until the surfaces 21 and 28 are in engagement and the rotation of the swift is braked,

causing slippage of the belt 8 on the pulley 7. The speed of rotation of the swift is reduced and less windings of weft thread are wound on the swift so that the surplus windings riding up on the surfaces 46 gradually disappear and the levers 15 move in clockwise direction until they are once more in the position shown in FIG. 1. The brake surface 21 is now disengaged from the surface 28 and there is no slippage between the belt 8 and the pulley 7 so that the swift can rotate at its previous speed.

The arrangement shown in FIGS. 1 to 3 does not include means for increasing the speed of the swift when more weft thread is pulled through the eye 43 than is supplied through the eye 12 and the normal speed of the swift must be somewhat greater than is required for continuously delivering an average length of weft thread per time unit. Braking of the swift by the aforedescribed mechanism causes reduction of the speed of the swift to the speed needed for delivering the normally required amount of thread.

FIG. 4 shows only the more important parts of a modified swift and also a weft thread storage spool 14, unwinding of weft thread from which is accompanied by formation of a balloon 41. Equivalent parts are designated by like numerals in FIGS. 1 to 4. The element 6, which is rotatably supported by the free end portion of the stationary shaft 5, is provided with an annular rim 25 which rotates with the swift. The annular rim 25 carries a traveler 24 through which extends the thread 23 unwinding from the swift. The centrifugal forces produced by the balloon 41 formed by the thread 23 and of the traveler 24 determine the friction effect produced by the relative movement of the rim 25 and the traveler 24.

If no thread is pulled through the eye 43, the traveler 24 does not move relatively to the rim 25 and the traveler as well as the balloon 41 rotate at the same speed as the swift. If thread is pulled through the eye 43, the traveler 24 moves relatively to the rim 25 in a direction which is opposite to the direction of rotation of the rim. If the same length of thread is pulled through the eye 43 as is running on the swift through the eye 12, the rotational speed of the traveler 24 relative to the rotational speed of the rim 25 is the same as the rotational speed of the rim 25 relative to the shaft 5, but in opposite direction; the traveler, therefore, stands still and the balloon 41 disappears. If more thread is unwound from the swift than is wound thereonto, the absolute rotational speed of the traveler 24 remains opposite, but is greater than the rotational speed of the rim 25. The traveler 24 assures that a balloon 41 is maintained also when no thread is pulled through the eye 43 so that thread is not unwound from the swift by gravity, as may be the case when working with heavy yarns.

The abscissa of the diagram shown in FIG. 5 represents time t and the ordinate represents the velocity v at which a weft thread is inserted in the shed. Curve 26 shows the velocity of the weft thread caused by the consecutive passages of shuttles through the shed. The velocity varies between zero at the points marked A and a maximum at the points marked B. The shaded area C corresponds to the length of weft thread inserted in the shed of the loom per pick. The dash-dot line 27 represents the constant speed at which weft thread supplied by the storage spool 14 in FIG. 4 is wound onto the swift. The straight line 27 is at least so high above the abscissa that the area of the shaded rectangle D is equal to the area .0.

In the diagram shown in FIG. 6 the abscissa represents time t and the ordinates represent the absolute rotational speed n of the traveler24 and of the balloon 41. At the points marked F no thread is pulled from the swift and the negative rotational speed n and the direction of movement of the traveler 24 and of the balloon 41 are the same as the rotational speed of the swift. No thread is pulled from the swift during the time when an idle shuttle is prepared for the subsequent pick. At the points marked E the length of weft thread unwound per time '5 unit from the swift is equal to the length of weft thread wound onto the swift and the absolute speed n of the traveler is zero; the traveler 24 stands still and the balloon 41 disappears. At the points marked G the rotational speed is the same as at the points marked F, but the direction of rotation is opposite. In other words, the rotational speeds of the traveler 24 and of the balloon 41 are equal to the difference between the maximal unwinding speed and the constant winding speed divided by the circumference of the rim 25. The direction of rotation of the balloon 41 is opposite to the direction of rotation of the swift. The rotational speed of the balloon at the points G is never greater than the difference between the maximal unwinding and the constant winding speed divided by the circumference of the rim 25. In conventional looms for weaving where there is no intermediate accumulating swift, the maximal rotational speed of the balloon formed at the thread storage spool is equal to the maximal speed at which the weft thread is inserted into the shed divided by the circumference of the storage spool at the respective moment. Due to the very great maximal weft insertion velocity the maximal rotational speed of the balloon in conventional arrangements is very great, causing great stress, particularly when the diameter of the storage spool becomes small as is the case when the thread on the storage spool becomes exhausted.

The embodiments of the invention shown in FIGS. 1 to 4 show a weft thread accumulating swift whereby the Weft thread is wound on the outside runs of the belts 1. FIG. 7 illustrates a device where the weft thread is wound on the inside runs of the belts. The device shown in FIG. 7 comprises a tubular member or hollow shaft 63 mounted on a portion 61 of the loom and held fast thereon by a screw connection 62. A hollow cylindrical part of an element 6' is rotatably supported by the member 63 by means of two ball bearings 64 and 65. Belt drives corresponding to the belt drives 1, 2, 3, of the device shown in FIG. 1 are rotated about the longitudinal axis of the member 63 in the same Way as the beltdrives are rotated in the embodiment shown in FIG. 1. The device shown in FIG. 7 may be used in vertical or horizontal position. The Worm Wheels 10 are driven by a worm 9 formed on the member 63. Rollers 66 and 67 forming a nip are rotatably mounted in an aperture in the member 63 and are placed in a radial plane including the rotation axis of the swift formed by the element 6 and the belts 1. The roller 66 is driven by bevel gears 68, 69, the latter being mounted on a shaft 71 to which a gear 72 is rigidly connected. The teeth of the gear 72 engage internal teeth 73 provided on the cylindrical portion of the element 6'. Weft thread is supplied through the interior of the mem ber 63 and seized in the nip formed by the rollers 66 and 67. The gears 73, 72 and 69, 68 are so dimensioned that the circumferential speed of the rollers 66 and 67 substantially equals the circumferential speed of the inside of the inner runs of the belts 1.

The weft thread 23 coming from the storage spool, not shown, is applied by the rollers 66, 67 to the inside of the inner runs of the belts 1 and held thereon by centrifugal force so that a layer 22 of windings is formed. The thread 23 unwound from the layer 22 is removed through the hollow 74 of the element 6' and conducted to the shuttles.

The aforedescribed swi'fitlike devices may include, for example, four belt drives or six belt drives, or only two belt drives. Instead of narrow belts, ribbons may be used made of elastic material and having a width corresponding to a considerable portion of the circumference of the layer of windings to be produced by the swift. In this case, rather long, barrel-shaped rollers may be used instead of the rollers shown in FIGS 1 to 3. An essential feature of the device according to the invention is that the layer 22 is moved in axial direction of the swift.

Instead of the illustrated and described means for automatically regulating the speed of the swift, other con- 6 ventional devices may be employed, for example, an optical regulating device. In this case an undue increase of the axial extension of the layer 22 may cause interruptionof a light beam and a lightsensitive device may be employed for reducing the rotational speed of or for temporarily stopping the swift. The light beam is not interrupted when the rotational speed is normal. A second light beam may be provided which is interrupted when the layer 22 has the desired axial extension and is not interrupted when the length of the thread layer 22 is less than a predetermined The uninte-r rupted second light beam meets a light-sensitive control device which causes speeding up of the swift until sufficient thread is wound onto the swift to produce the desired length of the layer 22.

When using a system according to the invention, small diameter spinning cops may be used instead of storage spools of large diameter.

I claim:

1. In a weaving machine of the gripper shuttle type wherein weft thread is supplied. from a storage spool located outside of a shed formed by wlarp threads:

a rotatable wefit thread accumulating device continuously rotating at a relatively slow speed,

stationary shaft means having an end portion rotatably supporting said device and having a free end, said device including thread carrier means movable substantially parallel with the rotation axis of said device,

the weft thread being substantially continuously unwound from [the storage spool and substantially continuously wound in a single layer around said carrier means coaxial of the rotation axis of said accumulating device, the weft thread being intermittently pulled and unwound at relatively speed from said layer,

stationary weft thread guide means located coaxial of said device and opposite the free end of said end portion of said shaft means,

said guide means directly receiving the wefit thread from said device for unwinding the thread from said layer in a direction substantially parallel with the rotation axis of said device, and

speed control means connected to said rotatable device and including means adapted to sense the axial extent of said layer of weft thread for controlling the rotational speed of said device in response to the axial extent of said layer.

2. Ln a Weaving machine of the gripper shuttle type wherein weft thread is supplied from a storage spool located outside of a shed formed by wlarp threads:

a rotatable weft thread accumulating device continuously rotating at a relatively slow speed, stationary shaft means having an end portion rotatably "supporting said device and having a free end,

said device including thread carrier means movable substantially parallel with the rotation axis of said device,

the weft thread being substantially continuously unwound from the storage spool and substantially continuously wound in a single layer around said carrier means coaxial of the rotation axis of said accumulating device, the weft thread being intermittently pulled and un wound at relatively high speed from said layer,

stationary weft thread guide means located coaxial of said device and opposite the free end of said end portion of said shaft means,

said guide means directly receiving the weft thread from said device for unwinding the thread from said layer in a direction substantially parallel with the rotation axis of said device,

said weft thread accumulating device including pairs of rollers placed in radial planes including the rotation axis of said device, the rollers of each pair being spaced in axial direction and being spaced from the rotation axis of the device,

an endless belt supported by the rollers of each pair and having runs longitudinally of the rotation axis of the device,

one of said runs of said belts forming said thread carrier means,

means for rotating one of the rollers of at least one pair for moving the respective belt and advancing the layer of weft thread wound on said carrier means coaxial of the rotation axis of the device,

support means rotatable on said stationary shaiit means and rotatably supporting said rollers, a worm on said shaft means, a worm wheel engaged by said worn and associated with one roller of at least one pair of said rollers for driving the respective endless belt upon notation of said support means around said shaft means,

means sensing the axial extent of said layer of weft thread, and

control means connected to said sensing means and to said support means for controlling the rotational speed of the latter in response to the axial extent of said layer.

3. In a weaving machine according to claim 2 and wherein the outer runs of said belts form said thread carrier means, said sensing means including a lever pivotally connected to said support means for swinging in a radial plane including the rotation axis of said support means, said lever having an arm having a portion adjacent to the outer run of one of said belts, said arm having a surface portion inclined with respect to the rotation axis ofsaid'sup'port means and having an end facing the end of the layer of weft thread Wound on said carrier means, the distance of said end of said surface portion from the rotation axis of said support means being smaller than the distance of the outer surface of the run of said belt, to which said arm portion is adjacent, from the rotation axis of said support means, the distance of said surface portion from the rotation axis of said support means gradually increasing with increasing distance from the layer of weft thread wound on said carrier means, the thread wound on said carrier means running onto said surface portion upon advance of the thread layer beyond a location determined by said arm portion and pressing said arm portion toward the rotation axis of said support means and rocking said lever, said control means being responsive to the rocking of said lever.

References Cited in the file of this patent UNITED STATES PATENTS 576,175 Weaver Feb. 2, 1897 2,439,903 OConnell Apr. 20, 1948 2,508,502 Dijksman et al May 23, 1950 2,589,429 Pfarrwaller Mar. 18, 1952 2,662,556 Svaty Dec. 15, 1953 2,720,223 Svaty Oct. 11, 1955 FOREIGN PATENTS 1,089,696 Germany Sept. 22, 1960 352,454 Great Britain June 29, 1931 

1. IN A WEAVING MACHINE OF THE GRIPPER SHUTTLE TYPE WHEREIN WEFT THREAD IS SUPPLIED FROM A STORAGE SPOOL LOCATED OUTSIDE OF A SHED FORMED BY WARP THREADS: A ROTATABLE WEFT THREAD ACCUMULATING DEVICE CONTINUOUSLY ROTATED AT A RELATIVELY SLOW SPEED, STATIONARY SHAFT MEANS HAVING AN END PORTION ROTATABLY SUPPORTING SAID DEVICE AND HAVING A FREE END, SAID DEVICE INCLUDING THREAD CARRIER MEANS MOVABLE SUBSTANTIALLY PARALLEL WITH THE ROTATION AXIS OF SAID DEVICE, THE WEFT THREAD BEING SUBSTANTIALLY CONTINOUSLY UNWOUND FROM THE STORAGE SPOOL AND SUBSTANTIALLY CONTINUOUSLY WOUND IN A SINGLE LAYER AROUND SAID CARRIER MEANS COAXIAL OF THE ROTATION AXIS OF SAID ACCUMULATING DEVICE, THE WEFT THREAD BEING INTERMITTENTLY PULLED AND UNWOUND AT RELATIVELY HIGH SPEED FROM SAID LAYER, 